Epidemiological Trends of Malaria in Eastern Shan State, Myanmar 2000-2016

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Epidemiological Trends of Malaria in Eastern Shan State, Myanmar 2000-2016 Ba Soe Thet1,2*, Witaya Swaddiwudhipong3, Krongthong Thimasarn4, Aung Thi5, Than Naing Soe6, Zaw Lin7 1 International Field Epidemiology Training Programme, Epidemiology Division, Ministry of Public Health, Thailand2 Vector Borne Disease Control Unit, Eastern Shan State, Myanmar 3 Mae Sot General Hospital, Tak Province, Ministry of Public Health, Thailand 4 Department of Disease Control, Ministry of Public Health, Thailand 5 Department of Public Health, Ministry of Health and Sports, Myanmar 6 Department of Public Health, Ministry of Health and Sports, Myanmar 7 Eastern Shan State Public Health Department, Ministry of Health and Sports, Myanmar

*Corresponding author, email address: [email protected]

Abstract Malaria is a priority communicable disease in Eastern Shan State (ESS) of Myanmar. This study aimed to describe the malaria situation, epidemiology and treatment services in ESS during 2000-2016. Data from township malaria monthly reports in ESS during 2000-2016 were analyzed by time, place, person, species and treatment services. Malaria morbidity, mortality and case-fatality rate decreased from 25.0 to 3.7 per 1,000 population, 15.0 to 0.2 per 100,000 population and 4.6% to 1.3%, respectively, during 2000-2016. The male to female ratio was 3:2 and those over 15 years old constituted 60% of all cases. The number of cases declined by 88% and 99% among those younger than 5 years of age and pregnant women, respectively. During 2011-2016, the case detection rate increased from 2% to 12%, and 94% of blood examinations used a rapid diagnostic test. Plasmodium vivax (63%) was the most prevalent parasite species, followed by Plasmodium falciparum (33%) while mixed parasites accounted for 4% of all infections. Non-government-controlled areas contributed more than 80% of cases between 2013 and 2016. Remarkable reductions in malaria morbidity and mortality in ESS followed improvements in early detection, appropriate treatment and effective vector control. However, the overwhelming contribution on caseload in non-government-controlled areas remain a challenge for the elimination of malaria in Myanmar.

Keywords: malaria, morbidity, mortality, annual blood examination rate, Eastern Shan State, Myanmar

Introduction incidence of malaria to less than one case per 1,000 population in all states/regions by 2020 by scaling up In 2015, there were an estimated 212 million cases of malaria control interventions.2 malaria and 429,000 malaria-related deaths globally. Eastern Shan State (ESS) is situated in the most In the South-East Asia Region, about 1.4 billion eastern part of Myanmar and consists of ten people were at risk of malaria, with 237 million at townships, eight sub-townships, 71 wards, 147 village high risk in 2015.1 Malaria in Myanmar contributed tracts and 2,063 villages with a population of approximately two-thirds of both morbidity and approximately 800,000. According to area micro- mortality in the Greater Mekong Subregion during stratification of ESS in 2015, about 53% and 28% of 2013.1 As a result, the National Malaria Control the population lived in malaria risk areas and Programme (NMCP) was developed in coordination with both international and local agencies, including probable risk areas, respectively. Because of the high the World Health Organization to reduce the proportion of the population at risk of infection, 84

OSIR, September 2019, Volume 12, Issue 3, p.84-92 community-based malaria control interventions were reported malaria cases: outpatients (OP): those who developed and have been implemented since 2007 in had uncomplicated malaria, and inpatients (IP): those ESS to increase accessibility of quality diagnosis and who had severe malaria, were hospitalized and had a effective treatment, especially in remote areas.3 For high risk of death.4 example, microscopy has been used for malaria The OP malaria case definition varied from year to diagnosis in health centers where microscopes are year depending on the type of blood test performed. available and malaria rapid diagnostic tests (RDTs) In the past, the NMCP diagnosed patients with have been used in all healthcare settings ranging positive blood films as “confirmed malaria cases” and from health centers to the community level. The basic “clinically suspected cases” based on clinical reporting units are village health volunteers (VHVs) symptoms. In 2006, the NMCP introduced, to some and basic health staffs. All examined cases are health centers, RDT which could detect only P. recorded in carbonless case registers and reported falciparum species. Since 2011, the NMCP has been monthly.4 distributing (through the State VBDC) bivalent RDTs, Eastern Shan State has experienced many malaria which can diagnose P. falciparum and P. vivax epidemics. One major epidemic occurred during 2001 malaria and, therefore, all malaria cases were in which an estimated 10,000 persons were affected regarded as confirmed cases.4 with 1,066 reported deaths in 23 villages.3 In addition, because ESS contains many so called "special Data Analysis regions" (politically unstable areas), non-government We analyzed data between 2000 and 2016 for controlled areas, and extremely hard-to-reach areas, morbidity and mortality rates, OP and IP malaria it is classified as a high risk malaria area.3,5 cases and deaths by time and township. We also Consequently, the extent of malaria and treatment described the distribution of cases by type of service service coverage is largely unknown. The objective of (i.e. health facility, village health volunteer and this study was to describe the malaria epidemiology NGO/INGO), gender age and species from 2011-2016 and coverage of treatment services in ESS during because data prior to this period were not available. 2000-2016 in the presence of malaria intervention We calculated the annual blood examination rate activities. (ABER) and annual parasite incidence (API) and used ArcGis 10.1 software for mapping. Methods Descriptive statistics including frequency, rates and We conducted a descriptive study on malaria in ESS proportions were computed. We calculated malaria during 2000-2016. morbidity rates per 1,000 and malaria mortality rates Data Sources and Data Collection per 100,000. We calculated ABER from the number of patients examined by microscopy or RDT per 100 We reviewed aggregated data on malaria cases and population and API rate per 1,000 population at-risk.6 deaths during 2000 – 2016 from the Vector Borne Disease Control (VBDC) programme at the state level. Results The data included monthly reports, carbonless Malaria Morbidity and Mortality Rates, 2000-2016 registers from townships, State VBDC annual reports Figure 1 shows the trends of malaria morbidity (per and reports from international non-governmental 1,000 population) and mortality rates (per 100,000 organizations (INGOs) and non-governmental population) in Eastern Shan State between 2000 and organizations (NGOs). However, malaria data of time, 2016. The morbidity and mortality rates gradually place, person and type of species were not available declined between 2000 and 2009 and then remained before 2011. Data on case detection and management fairly steady over the next 7 years. In 2000, the by type of service are available only after 2012. malaria morbidity rate was 25 per 1,000 and the Operational Definition mortality rate was 15 per 100,000 population. In 2016, the malaria morbidity rate was 3.7 per 1,000 and the A confirmed malaria case was defined as a patient mortality rate was 0.2 per 100,000. The highest whose blood film was positive by microscopy or rapid morbidity rate (29.4/1,000) and mortality rate diagnostic test (RDT). There were two types of (19.4/100,000) were reported in 2001.

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Figure 1. Trends of malaria morbidity rate (per 1,000 population) and mortality rate (per 100,000 population) in Eastern Shan State, Myanmar, 2000-2016.

Note: RDT: rapid diagnostic test.

Proportion of Malaria among All Hospital Cases and lowest morbidity rate (12.4/1,000). In 2016, there was Deaths, 2000-2016 a 78% reduction in morbidity rate and a 96% reduction in mortality rate in Mong Tong Township In 2000, there were 11,810 reported outpatient (OP) compared to 2000. The lowest morbidity rate in 2016 and 1,801 inpatient (IP) malaria cases. Only 83 among all townships was in Mong Lar (0.1/1,000). malaria deaths were reported. The highest peak of OP and IP cases occurred in 2003 (16,102 and 2,144 Coverage of Case Detection and Annual Blood cases, respectively). Between 2000 and 2016, there Examination Rate by Township was a 75% reduction in OP malaria cases, a 92% Figure 3 shows the annual blood examination rates reduction in IP cases and a 98% reduction in malaria (ABER) in Eastern Shan State according to township deaths. The proportion of malaria cases among total in 2000, 2005, 2010 and 2016. In 2000, all the patients decreased among both OP and IP cases. In townships reported an ABER of less than 5.0% except 2000, there were 80,567 out-patients, of whom 11,801 for Mong Hsat Township which had an ABER of (14.6%) were malaria cases while of the 253,443 out- 10.6%. Case detection rates increased over the years patients in 2016, only 2,917 (1.2%) were malaria from 2000 to 2016. In 2016, all townships reported an cases. A decrease in the proportion of IP malaria ABER of more than 5.0% and Mong Yang township cases was similarly observed. In 2000, there were 330 had the highest rate of 29.4%. deaths from all causes in hospitals of which 83 (25.2%) were from malaria. In 2016, of 126 deaths in hospitals, Distribution of Malaria Cases by Month only 2 (1.6%) were malaria-related. The overall Malaria cases occurred throughout the year but were malaria case fatality rate (CFR) reduced during 2000- highest during the rainy season (June to August). 2016. However, in 2015 and 2016, there were two peaks: Malaria Morbidity and Mortality Rates by Township one in the rainy season and the other in the early winter months. Each year, the majority of reported Figure 2 shows the malaria morbidity (2a) and cases were male (60%). mortality (2b) rates in Eastern Shan State according to township in 2000, 2005, 2010, and 2016. The From 2011 to 2016, malaria was reported among all morbidity and mortality rates declined in all age groups, but those aged 15 years and above townships during 2000-2016. In 2000, Mong Tong constituted 60% of all cases. Figure 4 shows the Township had the highest malaria morbidity and trends in malaria incidence among children aged less mortality rates (56.4/1,000 and 52.8/100,000, than 5 years and pregnant women in Eastern Shan respectively) while Mong Yaung township had the State during 2000-2016. The incidence of malaria

OSIR, September 2019, Volume 12, Issue 3, p.84-92 among children aged under 5-years and pregnant Plasmodium falciparum and mixed infections women decreased from 2000 to 2016. There were accounted for 63%, 33% and 4% of confirmed cases. 2,385 malaria cases among children aged less than 5 Malaria Case Management years in 2000 and this number decreased to 385 in 2016. Although the incidence of malaria in children Malaria case management was done not only in aged under 5 years declined by approximately 88.4% public health facilities but also in communities by over this period, the proportion of malaria cases in village health volunteers (VHVs) trained by the this age group to all cases remained at 11%. For NMCP. In addition, both national and international pregnant women, there were 663 malaria cases in NGOs also conducted case management through 2000 and only 6 cases in 2016 (99.5% reduction). mobile and fixed clinics. Data from VHVs and NGOs were not available during 2012 to 2014; although Malaria Diagnosis and Species Distribution those services did implement malaria case detection A total of 251,931 cases were examined during 2011 services. In 2015, 70.7% of cases were treated at a to 2016 by both microscopy and RDT to identify public health facility, while 19.6% were treated by confirmed malaria cases. Among all cases examined, VHVs and 9.8% by NGOs. The proportion of cases most (94%) were detected by RDT and only 6% were treated by VHVs and NGOs implementing partners diagnosed by microscopy. Plasmodium vivax, were22.9% and 12.4%, respectively, in 2016.

2a)

Figure 2. Malaria morbidity and mortality rates in Eastern Shan State, Myanmar according to township, 2000, 2005, 2010, and 2016 (1) 87

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2b)

Figure 2. Malaria morbidity and mortality rates in Eastern Shan State, Myanmar

according to township, 2000, 2005, 2010, and 2016 (2)

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Figure 3. Annual blood examination rates (ABER) in Eastern Shan State according to township, 2000, 2005, 2010 and 2016

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Figure 4. Number of malaria cases among children aged less than 5 years old and pregnant women in Eastern Shan State, 2000-2016 Discussion those who live in remote areas of the state. We observed changing patterns of malaria seasonality in The decreasing trends in malaria morbidity, 2015-2016, i.e. having two peaks of reported cases as mortality and case fatality rate in Eastern Shan State compared with only one peak in other years which during 2000-2016 coincided with the expansion of might be due to environmental factors, such as three key interventions: the distribution of long- temperature and humidity which can affect vector lasting insecticidal nets (LLINs), early malaria densities. This finding is consistent with the seasonal diagnosis and effective treatment. This finding is patterns in other states/regions of Myanmar.12 A consistent with other studies conducted in Africa study conducted in Burkina Faso on data recorded where a dramatic decline in malaria burden was due during 1999–2003 revealed that the highest malaria to the effective vector control measures and scaling mortality was during and at the end of the wet season up of artemisinin-based combination therapies (ACT) when the transmission intensity of malaria is at its as first line anti-malarial drugs.7-9 The increase in highest.13 morbidity rates during 2012-2016 might be due to the increase in reporting rates. This finding is consistent Malaria morbidity and mortality varied widely with a study conducted in South Sudan during 2006 between townships. This might be due to the varying and 2013 where a gradual increase in the number of ecological conditions. Mong Tong Township retained malaria cases was due to improvement of the its position as the township with the highest malaria surveillance system and increasing reporting rates.10 rates for a decade. In 2000, all townships had low Human migration is another possible factor that ABER indicating low coverage of diagnostic and might contribute to an increasing number of cases treatment services. In 2016, there was improvement during that period because migrant workers are in case finding as ABER increased from 2.0% to highly exposed to poor housing which lack preventive 12.5% by intensification of case finding through measures such as LLINs.11 mobile clinics, expansion of health facilities in special regions, capacity building of basic health staff and Total patient attendance at a health facility due to VHVs and increased reporting by NGOs.3 any illness during 2000-2016 increased by 57%, whereas malaria patient attendance decreased by Similar to other studies conducted in Myanmar, 77%. Therefore, reduction in malaria cases might not males and adults had higher malaria incidences be due to a decrease in accessibility. However, compared to females and other age groups, accessibility of health services is still challenging for respectively, which might be due to occupation and 90

OSIR, September 2019, Volume 12, Issue 3, p.84-92 behavioral patterns that cause a greater exposure to Recommendations vectors.7 The proportion of malaria in children under Routine malaria surveillance should be strengthened 5 years old was fairly constant at around 10%, to ensure complete and timely reporting from all indicating a persistent local transmission. The health sectors including public and private health number of reported malaria cases among pregnant facilities, NGOs, and Ethnic Health Organizations. women also decreased during the study period, which Transmission reduction activities such as probably indicates a more effective integration of intensification of case detection in hard-to-reach maternal and children health care and malaria areas, early case detection, appropriate treatment programme.2 The gender and age distribution pattern and effective vector control measures should be of malaria in Myanmar is different from the African scaled-up to be ready for malaria elimination. Strong settings where younger age group and pregnant political commitment should be maintained with women are the most affected populations.14 adequate financial support for malaria elimination. Blood examination by microscopy decreased whereas Acknowledgement the use of RDTs increased. This could be because microscopy can be performed only at hospitals We would like to express our sincere gratitude to the whereas RDTs can be used in all health facility State Public Health Department, Eastern Shan State, levels.4 Regarding parasite species, since bivalent Myanmar for providing necessary documents to carry RDT was used throughout 2011-2016, we can assume out this study. We are also grateful to Mr. Myo Min that the proportion of P. vivax increased due to the Htet, data assistant from the State Vector Borne high sensitivity of P. falciparum to artemisinin-based Disease Control unit, Eastern Shan State, for combination therapy. Prior to 2011, the proportion of surveillance data entry. The authors also thank Dr. P. vivax infections was low because only monovalent Zaw Lin, Deputy Director of Vector Borne Disease RDT, which can detect only P. falciparum, was in Control, for his advice on data analysis. use.4 This study supports the increasing roles of Suggested Citation VHVs and NGOs in diagnosing malaria with RDTs, treatment with artemisinin-based combination Thet BS, Swaddiwudhipong W, Thimasarn K, therapy and reporting in 2015-2016. Thi A, Soe TN, Lin Z. Epidemiological trends of malaria in Eastern Shan State, Myanmar 2000- Limitations 2016. OSIR. 2019 Sep;12(3): 84-92. Due to data unavailability, we could not describe the distribution of malaria by gender, age and species References before 2011. Limitations in use of health facility data 1. World Health Organization. Strategy in in assessing trends in malaria should be kept in mind, malaria elimination in Greater Mekong Sub- especially in terms of service utilization and region (2015 – 2030). Geneva: World Health completeness of reporting. However, with the Organization; 2015. available data, we could describe the trends of 2. Department of Public Health, Myanmar malaria indicators and identify differences in malaria Ministry of Health and Sports. National epidemiology between townships which may be useful strategic plan; intensifying malaria control for better prioritization and targeting implementation. and accelerating progress towards malaria Conclusions elimination (2016-2020). Nay Pyi Taw: Myanmar Ministry of Health and Sports; The findings revealed that morbidity and mortality of 2017. malaria in Eastern Shan State decreased over the period under review. Mong Tong and Mong Hsat 3. Eastern Shan State Vector Borne Diseases Townships had the highest malaria incidence. Control Programme, Eastern Shan State Malaria morbidity varies according to gender and age Public Health Department. VBDC annual with males and those aged more than or equal 15 reports, 2000-2016. Keng Tung: Eastern Shan years old showing a higher incidence. Case detection State Public Health Department; 2016. rates increased over time in all townships due to 4. National Malaria Control Programme, increasing roles of village health volunteers and Department of Public Health. Annual VBDC NGOs and introduction of rapid diagnostic tests. report 2015. Nay Pyi Taw: Ministry of Health

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